I use to use this kind of worm 2 times at weeks. I have a large culture of Californian red Earthworm. Really easy to culture and quite productive. These worms eat everything you can imagine, but for using them as live food I use to feed them with premium rabbit food. I take the worm I will be consumer at the week and put them into a jar with some wet sand, and let them for few days in sand to get them clean of organic matter from soil of the culture.

Hey bros, after reading this thread regarding feeding earthworms, I was inspired to collect some earthworms on my own. I went around the neighborhood and ?backyards? couldn?t seem to find any of these illusive tasty morsels for them goldfishes. Are earthworms like frogs being a sign of how healthy our lands are? If that?s the case our lands are seriously malnutrition. But guess that efforts paid off, finally found a few of them in a dark and damped patch of earth. Walla! They are there, but harvest wasn?t bountiful managed to only get about five? I?ll try again soon! Keep you bros posted!

here is a link to Vermicompost:http://youtu.be/gbjX2tt-oQw
vermicomposting is a technique for creating compost (nutrient rich soil) for your garden.

Basically, all you need is a handful of earthworms from local fishing shop or aquarium shops, a plastic tub, drill some holes to allow some air circulation, then all you do is pile a bunch of soggy newspaper or leaves at the bottom, a little bit of soil, then just put in leftover vegetable food scraps from your kitchen every few days, and the worms will digest them all, poop and create a pile of healthy soil you can use for your garden... and at the same time, they will reproduce and you can just feed the smaller younger worms to your goldfish (there will be worms of all sizes, from new born, to full grown adult, so regardless what size your fish are, you will have the right size worm to feed your fish... and these worms are nutrient rich, because they've been digesting all kinds of healthy vegetables leftovers you put into the bin.

as you can see in this picture, some are extremely tiny, that should be suitable even for your younger fish.

It's a simple and great way of having a constant supply of earthworms, and if you're into gardening, you'll also have plenty of rich soil that are fantastic for your plants as well (even if you dont feed that much earthworms to your fish or feed them earthworm that frequently, you can always just bag up some of the compost+worms and dump them at a local park or bottom of any tree for that matter.

-------- the three different types of earthworms ------- in case you plan on starting a vericompost

Endogeic. This category of worms typically live throughout the deeper soil layers into the mineral horizon. Endogeic worms build complex horizontal burrow systems. These worms rarely come to the surface, instead spending their lives in these burrow systems where they feed on decayed organic matter and bits of mineral soil. Further details of endogeic worm behavior are poorly known. These types of earthworms are not composting worms.

Anecic. The most famous type of anecic earthworm is the Common or Canadian Nightcrawler (Lumbricus terrestris). This category of earthworm form semi-permanent, vertical burrows that extend from the soil surface down through the mineral soil layer. Anecic earthworms feed off of the decaying surface litter, pulling it down into it's burrows to feed underground.

Anecic worms typically have a flattened "tail" that bristle with tiny hairs, called setae, that can grip the burrow wall thus helping it to avoid being easily pulled out of the ground. These worms also need a stable burrow environment in order to thrive, do not do well in dense populations as well as take a long to mature and multiply. Again, this category of earthworm is not the composting type.

Epigeic. Epigeic earthworms are the type of earthworms used for composting. These worms form no permanent burrows and live on the soil surface and uppermost mineral layer. They feed in organic surface debris and are well adapted to rapidly changing environment of the soil surface. These are the types of worms you will use for composting as they are voracious eaters, thrive in a densely populated culture and are tolerant of a wide range of environmental conditions.

i wonder what type are sold at bait shops or aquarium shops :\
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*i read in another post that brine shrimp's nutritiou value is pretty poor unless you feed a large amount of it, so other suggested that bloodworms would be the better option, but how does bloodworms compare to earthworms(from vericompos that have been fed various vegetables and fruits leftover) in terms of nutritious value for the fish? would it be too much to feed it daily or every other day?

Earth worms are great grooming food and also are equivalent to Viagara to humans if you use them to your breeders but a word of warning.
They can also caused problems associated with feeding live food such as increasing risks of getting bacteria or protozoans.( internal problems such as bloating, dropsy and sudden or rapid mysterious deaths). To minimize the risks, cultivate your own compost rather than pick from unknown source. Clean, purge their guts and disable them before feeding as some large varieties can burrow through your fish intestine when swollow live. Just thought I share my experience